Doctors treating a Sierra Leone physician with Ebola defended their decision not to give him an experimental drug, saying Wednesday they feared it was too risky.
Calling it "an impossible dilemma," Doctors Without Borders explained in detail their decision in response to a New York Times story on the case. It would have been the first time the experimental drug was tried in humans.
The explanation came the same day that another top doctor from Sierra Leone died of the disease, further fueling a debate about how to apportion a limited supply of untested drugs and vaccines and whether they are even effective.
Ebola has killed more than 1,000 people and sickened nearly 2,000 in the current West African outbreak that has also hit Guinea, Liberia and Nigeria. Many of the dead are health workers, who are often working with inadequate supplies and protection.
At the time the experimental treatment was being considered for Dr. Sheik Humarr Khan, his immune system was already starting to produce antibodies suggesting he might recover, Doctors Without Borders said in the statement. Khan was also due to be transferred to a European hospital that would be more capable of handling problems that might arise, it said.
The experimental drug, ZMapp, is designed to boost the immune system to help it fight the virus. Since Khan's body was already producing an immune response, the doctors may have feared that any boost would kick it into overdrive.
In the end, the treating physicians decided against using the drug. They never told Khan of its existence because they felt it would be unethical to tell him of a treatment they might not use. Shortly after their decision, however, Khan's condition worsened, the statement said, and the company providing the medical evacuation decided not to transfer him. He died a few days later, on July 29.
"Every day, doctors have to make choices, sometimes difficult, about treatment for their patients," said the Doctors Without Borders statement. "Trying an untested drug on patients is a very difficult decision, particularly in the light of the `do no harm' principle."
ZMapp has since been used on two Americans and a Spaniard. The California-based company that makes the drug, Mapp Pharmaceuticals, has said that its supplies are now exhausted, and it will take months to produce even a modest amount.
The drug has never before been tested in humans, and it is not clear if it is effective or even harmful. The Americans are improving - although it is unclear what role ZMapp has played in that - but the Spaniard died Tuesday.
The last known doses of ZMapp arrived in Liberia on Wednesday, carried personally by Foreign Minister Augustine Ngafuan. The government has said they will be given to two sick doctors. They will be the first Africans known to receive the treatment.
But the debate over experimental treatments and vaccines will continue. Canada has promised to donate 800 to 1,000 doses of its untested Ebola vaccine to the World Health Organization and already questions are being asked about who will get it and how scientists will determine if it works.
Likely candidates for the vaccine are health care workers in Africa who are among the most vulnerable because of their close contact with Ebola patients.
Liberia has asked for the vaccine, and Guinea is considering asking for access to it.
Unlike ZMapp, which is being given to only a handful of people and is unlikely to yield significant information about the drug's effectiveness, the vaccine could be tested in a small, but more rigorous field trial.
"It gives us an opportunity to test the vaccine in an outbreak situation in populations that are at risk," said David Heymann, who professor at London School of Hygiene and Tropical Medicine.
Meanwhile, Nigeria confirmed that another person has died from Ebola, bringing the toll in that country to three. The man was under quarantine because he had contact with Patrick Sawyer, a Liberian-American who flew into Nigeria with the disease and died of it last month.